Abrasive sleeve holder



@wpt. 25, 1956 Filed Dec. 8, 1955 G. A. LARSON ABRASIVE SLEEVE HOLDER 2 Shee't s-Sheet 1L INVENTOR. a [W077 p 1151155 1956 e. A. LARSON 2,763,96

ABRASIVE SLEEVE HOLDER Filed Dec. 8, 1953 2 Sheets-Sheet 2 United States Patent 2,763,969 ABRASIVE SLEEVE HOLDER George A. Larson, Rockford, 11].; Alice R.

trix of said George A. Larson, Alice R. Larson, Rockford, Ill.

Larson, execudeceased, assignor to This application is a continuation-in-part of my application, Serial No. 273,061, filed February 23, 1952, which resulted in Patent No. 2,687,600, issued August 31, 1954.

This invention relates to a rotatable wheel-like holder for an abrasive sleeve in the form of an endless flexible band. The present improvements are concerned with the holder itself. It is produced mostly, if not entirely, from a resilient material, such as rubber (synthetic, natural, or mixed), with capacity for radial expansion in response to the centrifugal force that arises from rotation. The sleeve fitted around the periphery of the holder is, in consequence, subjected on its inner face to an outward expansion of the holder suflicient to tension the sleeve and secure it fixedly in place.

The present holder utilizes a roller body of rubber-like material formed with a plurality of symmetrically arranged holes which extend therethrough in a direction parallel with its axis. These holes are sized and spaced so as to provide between them solid webs which stretch or compress according to whether the holder is in motion or at rest. When an object is pressed against the sleeve, the holder will tend to yield inwardly, counter to the centrifugally developed force of expansion. By the improved construction disclosed herein, the yieldability of the holder is controlled so as to avoid relatively hard and soft spots at different points in its periphery.

My invention aims to produce a circular holder of the kind described which, although yieldable in response to pressure from the work, provides a substantially constant resistance at all points. It also aims to accomplish this objective by means which is simple and inexpensive and long-lived, and in which there is ample aeration to maintain a relatively cool condition of the holder. The holder itself consists of a one-piece roller, produced by a molding operation or otherwise, so as to involve the minimum of expense in its manufacture.

A holder which attains these various objectives is illustrated in two different forms in the accompanying drawings wherein- Fig. 1 is a view in end elevation of the holder;

Figs. 2 and 3 are similar fragmentary views thereof, showing a localized displacement of the holder body in response to peripheral pressure applied at points designated by the radial lines 22 and33, respectively, and

Figs. 4 and 5 are views similar to Figs. 1 and 2, but illustrating a modified or alternative construction.

The same reference numerals are applied to corresponding parts throughout the views.

Referring first to Figs. l-3, the holder H is in the form of a roller body having a diameter that is suitable for supporting therearound a sleeve S of predetermined peripheral length. The length of the holder axiswise corresponds generally with the width of a conventional sleeve, perhaps an inch or two. In the holder is a center hole which may be occupied by a bushing 13 arranged for fitting upon a supporting rotary spindle (not shown) V inner holes i so whereby rotation is transmitted to the holder and to the sleeve carried thereby.

The circular holder body is formed of a suitable rubberlike material. This is desirably a relatively soft rubbernatural, synthetic, or otherwise. When rotated, centrifugal force produces a radial expansion of the holder body, tending to enlarge its diameter; when at rest, the holder body contracts again to its normal size.

To control the expansive movements of the holder body so as to maintain a substantially uniform condition of yieldability at every peripheral point is one of the principal objects of this invention. I accomplish this by pro viding a plurality of holes extending through the holder parallel to its axis. These holes are arranged in circular rows concentrically of the holder axis, those in the inner row designated as i, being all of one size, whereas those in the outer row, designated as 0, are all of another size. The holes 1' in the inner row are somewhat larger than those in the outer row, but are fewer in number by onehalf. As herein shown, nine holes i in the inner row are provided, and eighteen holes 0 in the outer row, the diameters of the former being greater by about one-third. All of the outer holes 0 are spaced equidistantly apart as are also the inner holes i, and each two adjacent outer holes are also spaced the same distance away from one of the that all the radial lines 2-2 passing through the centers of the inner holes 1' lie equidistantly between the proximate pairs of outer holes 0.

A holder so constructed is characterized by a first set of Webs a which extend radially between the inner holes 1' and by a second set of webs b which extend radially between the outer holes 0. The webs a and b traversed by the radial lines 3-3 define, in eifect, spokes which are continuous, whereas the radial lines 22 traverse only the outer webs b, thereby defining, as it were, spokes which are interrupted by the inner holes 1'. This special arrangement of webs, resulting from inner and outer circular rows of holes in one of which rows the number of holes is double that of the other, is responsible for a very effective performance of the holder as will now be explained.

In operation, the holder is revolved at a normal speed, as 1700 R. P. M., and a piece of work is held in pressure engagement with the sleeve S which is fitted around the holder to revolve therewith. The outer face of this sleeve carries a coating of abrasive material which contacts the work. The pressure applied by the work against the sleeve is often very considerable and also localized, and it is desirable that the holder body yield somewhat in response thereto. This yielding by the present holder body is so controlled that a uniform and even resistance is maintained at every peripheral point. The holder body should have this capacity for such yielding so that the sleeve may tend to flatten somewhat at the point where pressure is applied, particularly when the work face undergoing treatment is relatively flat.

With pressure exerted against the outer face of the sleeve, the holder will accordingly yield, and, in so doing, parts of its body structure will be displaced somewhat, as indicated in Figs. 2 and 3. Since the peripheral speed of the sleeve is quite fast, it is manifest that the radial lines 2-2 and 3-3 follow each other, and others in between, in rapid succession past the point of force application. The inward displacement of the holder body produces an ellipticity of each outer hole 0 with its long axis disposed transversely of the intersecting radial line. The webs b between adjacent pairs of outer holes resist this deformation and are backed up by the inner webs a at certain points, and by other webs c which join the bases of the intermediate webs b with the continuous spokes defined by the next adjacent aligned webs a and b. This displacement of the web structure of the holder at the peripheral point where a force is applied to the sleeve also produces an ellipticity of each inner hole i. At each such point a lateral displacement of the adjacent inner webs zralso takes place. Figs. 2 and 3 indicate only radial yield, such as would occur when the holder was rotating with very slight resistance to rotation exerted by the work in contact with the abrasive band S, but it is obvious that due to the fact that the rubber-like body H- constitutes substantially the entire radiusof the holder and has so many holes through it, as indicated at 0 and i, there is also appreciable torsional yield and resilience, and that is important from the standpoint of reducing the tendency for chatter in sanding. I have also found that the provision of so many holes 0 and i also improves the gripping of the band S on the periphery of the body H, title, evidently, to the greater radial yieldability mentioned before working both ways and causing the body to expand more readily under centrifugal force.

It is difficult to utilize a circular solid body of resilient material for an abrasive sleeve holder due to excessive weight and temperature generated in use. The provision of holes through the body to reduce this weight and temperature condition has not been satisfactory in the past, due to imbalance of the holder body and weakening of its structure with resulting non-uniformity in its resistance to yielding when a localized pressure is applied to its eriphery. By the. means herein described, however, these deficiencies of the past have been overcome. This results in pa t from the provision of inner and outer circular rows of holes, arranged concentrically of each other and of the circular holder body, with the inner holes the larger but only one-half the number of the outer larger holes, the peripheral portion of the holder body being preserved continuous and unbroken; thev holes so arranged are spaced apart substantially equidistantly from each other in the same row and from those inthe other row; and between adjacent holes in the inner row are. stretchable webs which are aligned with other stretchable webs between adjacent pairs of'holes inthe outer row, the remaining in-between webs between adjacent holes in the outer row being disposed radially oppositely of the, holes in the inner row. The body structure, so produced is light, well aerated, and deformable in response to a localized pressure at its periphery with a substantially uniform yieldability at every point whereby its abrasive sleeve is enabled to operate more effectively upon the work.

The other construction shown in Figs. 4 and 5 is similar, but the. holder H, has its roller body of rubber from its outer periphery all the way in to its center hole, the bushing B being omitted and the rubber body fitting rectly on the drive shaft and being adapted to be frictionall-y clamped from opposite sides to turn with the shaft. The outer holes 0 in this form are larger in diameter than. the corresponding holes 0 of the first form to reduce the thickness of webs b and. 0 proportionately and also reduce the thickness of webs. dbetween the holes 0 and the periphery of the roller body, to increase the yieldability. Another series of holes e is provided in circumterentially spaced relation on lines 33 at the 4 centers of the cross-shaped webs defined at the intersections of webs a, b, and 0, these holes e being quite small in relation to holes 0 and i and serving to further increase the yieldability of the roller body and make this yieldability more nearly uniform all around the circumference of the body by breaking the otherwise solid radial ribs on lines 3-3, to give about the same yield on those lines as on lines 22.

it is believed the foregoing description conveys a good understanding of the objects and advantages of'my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

I claim:

1. A rotary one-piece expansible abrasive sleeve holder of rubber-like material in the form of a roller in which the rubber-like body constitutes substantially the entire radius of the roller whereby to provide increased yield torsionally as well as radially, the roller body being formed therethrough with a plurality of substantially circular holes extending between its opposite ends and arranged in substantially parallel relation in at least two concentric circular rows at approximately half and three quarters of the way out from the center and with the holes in each row arranged in equally circumferentially spaced relation, the holes in the outer row being alike and appreciably smaller in diameter than the holes in the inner row which are also alike, and the number of holes in said inner row being but one-half the number of those in said outer row, the aggregate Width of the holes on any given radius of the roller being approximately equal to half the radius thereof, the arrangement of said holes being such that the webs between adjacent holes in said inner row are radially aligned with and connected to webs between adjacent holes in said outer row with the remaining in-between webs between adjacent holes in said outer row disposed radially opposite the holes in said inner row.

2. A sleeve holder according to claim 1 in which there is on a radius intermediate those of the inner and outer circles of holes a third circular row of substantially circu'lar holes that are appreciably smaller than the other holes provided in said body extending between its opposite ends in substantially parallel relation to the other holes and'arranged in equally circumferentially spaced relation at the centers of the cross-shaped webs defined at the intersections of the webs between the holes of the other two series, whereby to break the continuity of the webs between the inner holes radially aligned with the webs between the outer holes and accordingly increase yieldability of the roller body.

References Cited in the file of this patent UNITED STATES PATENTS 965,922 Merigoux Aug. 2, 1910' 1,495,083 Krusemark May 20, 1924 2,377,880 Gutsell June 12, 1945 2,415,308 Schulte a- Feb. 4, 1947 2,548,166 Larson Apr. 10, 1951 

